blob: 5464665f0b6aa7b86b472b080213715dcacfe5f4 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
David Brownelld49d4312005-05-07 13:21:50 -07002 * Copyright (C) 2001-2004 by David Brownell
David Brownell53bd6a62006-08-30 14:50:06 -07003 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the
6 * Free Software Foundation; either version 2 of the License, or (at your
7 * option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software Foundation,
16 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19/* this file is part of ehci-hcd.c */
20
21/*-------------------------------------------------------------------------*/
22
23/*
24 * EHCI hardware queue manipulation ... the core. QH/QTD manipulation.
25 *
26 * Control, bulk, and interrupt traffic all use "qh" lists. They list "qtd"
27 * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
28 * buffers needed for the larger number). We use one QH per endpoint, queue
29 * multiple urbs (all three types) per endpoint. URBs may need several qtds.
30 *
31 * ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with
32 * interrupts) needs careful scheduling. Performance improvements can be
33 * an ongoing challenge. That's in "ehci-sched.c".
David Brownell53bd6a62006-08-30 14:50:06 -070034 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
36 * or otherwise through transaction translators (TTs) in USB 2.0 hubs using
37 * (b) special fields in qh entries or (c) split iso entries. TTs will
38 * buffer low/full speed data so the host collects it at high speed.
39 */
40
41/*-------------------------------------------------------------------------*/
42
43/* fill a qtd, returning how much of the buffer we were able to queue up */
44
45static int
Stefan Roese6dbd6822007-05-01 09:29:37 -070046qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
47 size_t len, int token, int maxpacket)
Linus Torvalds1da177e2005-04-16 15:20:36 -070048{
49 int i, count;
50 u64 addr = buf;
51
52 /* one buffer entry per 4K ... first might be short or unaligned */
Stefan Roese6dbd6822007-05-01 09:29:37 -070053 qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr);
54 qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32));
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 count = 0x1000 - (buf & 0x0fff); /* rest of that page */
56 if (likely (len < count)) /* ... iff needed */
57 count = len;
58 else {
59 buf += 0x1000;
60 buf &= ~0x0fff;
61
62 /* per-qtd limit: from 16K to 20K (best alignment) */
63 for (i = 1; count < len && i < 5; i++) {
64 addr = buf;
Stefan Roese6dbd6822007-05-01 09:29:37 -070065 qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr);
66 qtd->hw_buf_hi[i] = cpu_to_hc32(ehci,
67 (u32)(addr >> 32));
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 buf += 0x1000;
69 if ((count + 0x1000) < len)
70 count += 0x1000;
71 else
72 count = len;
73 }
74
75 /* short packets may only terminate transfers */
76 if (count != len)
77 count -= (count % maxpacket);
78 }
Stefan Roese6dbd6822007-05-01 09:29:37 -070079 qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 qtd->length = count;
81
82 return count;
83}
84
85/*-------------------------------------------------------------------------*/
86
87static inline void
88qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
89{
Alek Du3807e262009-07-14 07:23:29 +080090 struct ehci_qh_hw *hw = qh->hw;
91
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 /* writes to an active overlay are unsafe */
93 BUG_ON(qh->qh_state != QH_STATE_IDLE);
94
Alek Du3807e262009-07-14 07:23:29 +080095 hw->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
96 hw->hw_alt_next = EHCI_LIST_END(ehci);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
Alan Sterna455212d2009-06-11 14:56:22 -040098 /* Except for control endpoints, we make hardware maintain data
99 * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
100 * and set the pseudo-toggle in udev. Only usb_clear_halt() will
101 * ever clear it.
102 */
Alan Stern4c53de72012-07-11 11:21:32 -0400103 if (!(hw->hw_info1 & cpu_to_hc32(ehci, QH_TOGGLE_CTL))) {
Alan Sterna455212d2009-06-11 14:56:22 -0400104 unsigned is_out, epnum;
105
Alan Sterne04f5f72011-07-19 14:01:23 -0400106 is_out = qh->is_out;
Alek Du3807e262009-07-14 07:23:29 +0800107 epnum = (hc32_to_cpup(ehci, &hw->hw_info1) >> 8) & 0x0f;
Alan Sterna455212d2009-06-11 14:56:22 -0400108 if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
Alek Du3807e262009-07-14 07:23:29 +0800109 hw->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
Alan Sterna455212d2009-06-11 14:56:22 -0400110 usb_settoggle (qh->dev, epnum, is_out, 1);
111 }
112 }
113
Alek Du3807e262009-07-14 07:23:29 +0800114 hw->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115}
116
117/* if it weren't for a common silicon quirk (writing the dummy into the qh
118 * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
119 * recovery (including urb dequeue) would need software changes to a QH...
120 */
121static void
122qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
123{
124 struct ehci_qtd *qtd;
125
126 if (list_empty (&qh->qtd_list))
127 qtd = qh->dummy;
128 else {
129 qtd = list_entry (qh->qtd_list.next,
130 struct ehci_qtd, qtd_list);
Pavankumar Kondeti3d037772012-09-07 11:23:28 +0530131 /*
132 * first qtd may already be partially processed.
133 * If we come here during unlink, the QH overlay region
134 * might have reference to the just unlinked qtd. The
135 * qtd is updated in qh_completions(). Update the QH
136 * overlay here.
137 */
Alan Sternfeca7742013-03-01 10:51:15 -0500138 if (qh->hw->hw_token & ACTIVE_BIT(ehci)) {
Pavankumar Kondeti3d037772012-09-07 11:23:28 +0530139 qh->hw->hw_qtd_next = qtd->hw_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 qtd = NULL;
Pavankumar Kondeti3d037772012-09-07 11:23:28 +0530141 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 }
143
144 if (qtd)
145 qh_update (ehci, qh, qtd);
146}
147
148/*-------------------------------------------------------------------------*/
149
Alan Stern914b7012009-06-29 10:47:30 -0400150static void qh_link_async(struct ehci_hcd *ehci, struct ehci_qh *qh);
151
152static void ehci_clear_tt_buffer_complete(struct usb_hcd *hcd,
153 struct usb_host_endpoint *ep)
154{
155 struct ehci_hcd *ehci = hcd_to_ehci(hcd);
156 struct ehci_qh *qh = ep->hcpriv;
157 unsigned long flags;
158
159 spin_lock_irqsave(&ehci->lock, flags);
160 qh->clearing_tt = 0;
161 if (qh->qh_state == QH_STATE_IDLE && !list_empty(&qh->qtd_list)
Alan Sterne8799902011-08-18 16:31:30 -0400162 && ehci->rh_state == EHCI_RH_RUNNING)
Alan Stern914b7012009-06-29 10:47:30 -0400163 qh_link_async(ehci, qh);
164 spin_unlock_irqrestore(&ehci->lock, flags);
165}
166
167static void ehci_clear_tt_buffer(struct ehci_hcd *ehci, struct ehci_qh *qh,
168 struct urb *urb, u32 token)
169{
170
171 /* If an async split transaction gets an error or is unlinked,
172 * the TT buffer may be left in an indeterminate state. We
173 * have to clear the TT buffer.
174 *
175 * Note: this routine is never called for Isochronous transfers.
176 */
177 if (urb->dev->tt && !usb_pipeint(urb->pipe) && !qh->clearing_tt) {
178#ifdef DEBUG
179 struct usb_device *tt = urb->dev->tt->hub;
180 dev_dbg(&tt->dev,
181 "clear tt buffer port %d, a%d ep%d t%08x\n",
182 urb->dev->ttport, urb->dev->devnum,
183 usb_pipeendpoint(urb->pipe), token);
184#endif /* DEBUG */
185 if (!ehci_is_TDI(ehci)
186 || urb->dev->tt->hub !=
187 ehci_to_hcd(ehci)->self.root_hub) {
188 if (usb_hub_clear_tt_buffer(urb) == 0)
189 qh->clearing_tt = 1;
190 } else {
191
192 /* REVISIT ARC-derived cores don't clear the root
193 * hub TT buffer in this way...
194 */
195 }
196 }
197}
198
Alan Stern14c04c02007-08-24 15:40:19 -0400199static int qtd_copy_status (
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 struct ehci_hcd *ehci,
201 struct urb *urb,
202 size_t length,
203 u32 token
204)
205{
Alan Stern14c04c02007-08-24 15:40:19 -0400206 int status = -EINPROGRESS;
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 /* count IN/OUT bytes, not SETUP (even short packets) */
209 if (likely (QTD_PID (token) != 2))
210 urb->actual_length += length - QTD_LENGTH (token);
211
212 /* don't modify error codes */
Alan Sterneb231052007-08-21 15:40:36 -0400213 if (unlikely(urb->unlinked))
Alan Stern14c04c02007-08-24 15:40:19 -0400214 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
216 /* force cleanup after short read; not always an error */
217 if (unlikely (IS_SHORT_READ (token)))
Alan Stern14c04c02007-08-24 15:40:19 -0400218 status = -EREMOTEIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219
220 /* serious "can't proceed" faults reported by the hardware */
221 if (token & QTD_STS_HALT) {
222 if (token & QTD_STS_BABBLE) {
223 /* FIXME "must" disable babbling device's port too */
Alan Stern14c04c02007-08-24 15:40:19 -0400224 status = -EOVERFLOW;
Alan Sternba516de2009-06-29 17:36:14 -0400225 /* CERR nonzero + halt --> stall */
226 } else if (QTD_CERR(token)) {
227 status = -EPIPE;
228
229 /* In theory, more than one of the following bits can be set
230 * since they are sticky and the transaction is retried.
231 * Which to test first is rather arbitrary.
232 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 } else if (token & QTD_STS_MMF) {
234 /* fs/ls interrupt xfer missed the complete-split */
Alan Stern14c04c02007-08-24 15:40:19 -0400235 status = -EPROTO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 } else if (token & QTD_STS_DBE) {
Alan Stern14c04c02007-08-24 15:40:19 -0400237 status = (QTD_PID (token) == 1) /* IN ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 ? -ENOSR /* hc couldn't read data */
239 : -ECOMM; /* hc couldn't write data */
240 } else if (token & QTD_STS_XACT) {
Alan Sternba516de2009-06-29 17:36:14 -0400241 /* timeout, bad CRC, wrong PID, etc */
242 ehci_dbg(ehci, "devpath %s ep%d%s 3strikes\n",
243 urb->dev->devpath,
244 usb_pipeendpoint(urb->pipe),
245 usb_pipein(urb->pipe) ? "in" : "out");
Alan Stern14c04c02007-08-24 15:40:19 -0400246 status = -EPROTO;
Alan Sternba516de2009-06-29 17:36:14 -0400247 } else { /* unknown */
248 status = -EPROTO;
249 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250
251 ehci_vdbg (ehci,
252 "dev%d ep%d%s qtd token %08x --> status %d\n",
253 usb_pipedevice (urb->pipe),
254 usb_pipeendpoint (urb->pipe),
255 usb_pipein (urb->pipe) ? "in" : "out",
Alan Stern14c04c02007-08-24 15:40:19 -0400256 token, status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 }
Alan Stern14c04c02007-08-24 15:40:19 -0400258
259 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260}
261
262static void
Alan Stern14c04c02007-08-24 15:40:19 -0400263ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264__releases(ehci->lock)
265__acquires(ehci->lock)
266{
Alan Stern2656a9a2012-11-08 10:17:01 -0500267 if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT) {
268 /* ... update hc-wide periodic stats */
269 ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 }
271
Alan Sterneb231052007-08-21 15:40:36 -0400272 if (unlikely(urb->unlinked)) {
273 COUNT(ehci->stats.unlink);
274 } else {
David Brownell4f667622008-04-12 08:32:05 -0700275 /* report non-error and short read status as zero */
276 if (status == -EINPROGRESS || status == -EREMOTEIO)
Alan Stern14c04c02007-08-24 15:40:19 -0400277 status = 0;
Alan Sterneb231052007-08-21 15:40:36 -0400278 COUNT(ehci->stats.complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
281#ifdef EHCI_URB_TRACE
282 ehci_dbg (ehci,
283 "%s %s urb %p ep%d%s status %d len %d/%d\n",
Harvey Harrison441b62c2008-03-03 16:08:34 -0800284 __func__, urb->dev->devpath, urb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 usb_pipeendpoint (urb->pipe),
286 usb_pipein (urb->pipe) ? "in" : "out",
Alan Stern14c04c02007-08-24 15:40:19 -0400287 status,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 urb->actual_length, urb->transfer_buffer_length);
289#endif
290
291 /* complete() can reenter this HCD */
Alan Sterne9df41c2007-08-08 11:48:02 -0400292 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 spin_unlock (&ehci->lock);
Alan Stern4a000272007-08-24 15:42:24 -0400294 usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 spin_lock (&ehci->lock);
296}
297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
299
300/*
301 * Process and free completed qtds for a qh, returning URBs to drivers.
302 * Chases up to qh->hw_current. Returns number of completions called,
303 * indicating how much "real" work we did.
304 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305static unsigned
David Howells7d12e782006-10-05 14:55:46 +0100306qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307{
Alan Stern3a444942009-08-19 12:22:06 -0400308 struct ehci_qtd *last, *end = qh->dummy;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 struct list_head *entry, *tmp;
Alan Stern3a444942009-08-19 12:22:06 -0400310 int last_status;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 int stopped;
312 unsigned count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 u8 state;
Alek Du3807e262009-07-14 07:23:29 +0800314 struct ehci_qh_hw *hw = qh->hw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
316 if (unlikely (list_empty (&qh->qtd_list)))
317 return count;
318
319 /* completions (or tasks on other cpus) must never clobber HALT
320 * till we've gone through and cleaned everything up, even when
321 * they add urbs to this qh's queue or mark them for unlinking.
322 *
323 * NOTE: unlinking expects to be done in queue order.
Alan Stern3a444942009-08-19 12:22:06 -0400324 *
325 * It's a bug for qh->qh_state to be anything other than
326 * QH_STATE_IDLE, unless our caller is scan_async() or
Alan Stern569b3942012-07-11 11:23:00 -0400327 * scan_intr().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 */
329 state = qh->qh_state;
330 qh->qh_state = QH_STATE_COMPLETING;
331 stopped = (state == QH_STATE_IDLE);
332
Alan Stern3a444942009-08-19 12:22:06 -0400333 rescan:
334 last = NULL;
335 last_status = -EINPROGRESS;
336 qh->needs_rescan = 0;
337
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 /* remove de-activated QTDs from front of queue.
339 * after faults (including short reads), cleanup this urb
340 * then let the queue advance.
341 * if queue is stopped, handles unlinks.
342 */
343 list_for_each_safe (entry, tmp, &qh->qtd_list) {
344 struct ehci_qtd *qtd;
345 struct urb *urb;
346 u32 token = 0;
347
348 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
349 urb = qtd->urb;
350
351 /* clean up any state from previous QTD ...*/
352 if (last) {
353 if (likely (last->urb != urb)) {
Alan Stern14c04c02007-08-24 15:40:19 -0400354 ehci_urb_done(ehci, last->urb, last_status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 count++;
Misha Zhilinb5f7a0e2008-02-27 18:05:24 -0800356 last_status = -EINPROGRESS;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 }
358 ehci_qtd_free (ehci, last);
359 last = NULL;
360 }
361
362 /* ignore urbs submitted during completions we reported */
363 if (qtd == end)
364 break;
365
366 /* hardware copies qtd out of qh overlay */
367 rmb ();
Stefan Roese6dbd6822007-05-01 09:29:37 -0700368 token = hc32_to_cpu(ehci, qtd->hw_token);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
370 /* always clean up qtds the hc de-activated */
Alan Sterna2c27062009-02-10 10:16:58 -0500371 retry_xacterr:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 if ((token & QTD_STS_ACTIVE) == 0) {
373
Vikram Pandita332960b2011-10-30 12:55:09 -0700374 /* Report Data Buffer Error: non-fatal but useful */
375 if (token & QTD_STS_DBE)
376 ehci_dbg(ehci,
377 "detected DataBufferErr for urb %p ep%d%s len %d, qtd %p [qh %p]\n",
378 urb,
379 usb_endpoint_num(&urb->ep->desc),
380 usb_endpoint_dir_in(&urb->ep->desc) ? "in" : "out",
381 urb->transfer_buffer_length,
382 qtd,
383 qh);
384
David Brownella082b5c2008-04-10 14:21:06 -0700385 /* on STALL, error, and short reads this urb must
386 * complete and all its qtds must be recycled.
387 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 if ((token & QTD_STS_HALT) != 0) {
Alan Sterna2c27062009-02-10 10:16:58 -0500389
390 /* retry transaction errors until we
391 * reach the software xacterr limit
392 */
393 if ((token & QTD_STS_XACT) &&
394 QTD_CERR(token) == 0 &&
Alan Sternef4638f2009-07-31 10:41:40 -0400395 ++qh->xacterrs < QH_XACTERR_MAX &&
Alan Sterna2c27062009-02-10 10:16:58 -0500396 !urb->unlinked) {
397 ehci_dbg(ehci,
Randy Dunlapd0626802009-02-13 11:22:06 -0800398 "detected XactErr len %zu/%zu retry %d\n",
Alan Sternef4638f2009-07-31 10:41:40 -0400399 qtd->length - QTD_LENGTH(token), qtd->length, qh->xacterrs);
Alan Sterna2c27062009-02-10 10:16:58 -0500400
401 /* reset the token in the qtd and the
402 * qh overlay (which still contains
403 * the qtd) so that we pick up from
404 * where we left off
405 */
406 token &= ~QTD_STS_HALT;
407 token |= QTD_STS_ACTIVE |
408 (EHCI_TUNE_CERR << 10);
409 qtd->hw_token = cpu_to_hc32(ehci,
410 token);
411 wmb();
Alek Du3807e262009-07-14 07:23:29 +0800412 hw->hw_token = cpu_to_hc32(ehci,
413 token);
Alan Sterna2c27062009-02-10 10:16:58 -0500414 goto retry_xacterr;
415 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 stopped = 1;
417
418 /* magic dummy for some short reads; qh won't advance.
419 * that silicon quirk can kick in with this dummy too.
David Brownella082b5c2008-04-10 14:21:06 -0700420 *
421 * other short reads won't stop the queue, including
422 * control transfers (status stage handles that) or
423 * most other single-qtd reads ... the queue stops if
424 * URB_SHORT_NOT_OK was set so the driver submitting
425 * the urbs could clean it up.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 */
427 } else if (IS_SHORT_READ (token)
Stefan Roese6dbd6822007-05-01 09:29:37 -0700428 && !(qtd->hw_alt_next
429 & EHCI_LIST_END(ehci))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 stopped = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 }
432
433 /* stop scanning when we reach qtds the hc is using */
434 } else if (likely (!stopped
Alan Sternc0c53db2012-07-11 11:21:48 -0400435 && ehci->rh_state >= EHCI_RH_RUNNING)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 break;
437
David Brownella082b5c2008-04-10 14:21:06 -0700438 /* scan the whole queue for unlinks whenever it stops */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 } else {
440 stopped = 1;
441
David Brownella082b5c2008-04-10 14:21:06 -0700442 /* cancel everything if we halt, suspend, etc */
Alan Sternc0c53db2012-07-11 11:21:48 -0400443 if (ehci->rh_state < EHCI_RH_RUNNING)
Alan Stern14c04c02007-08-24 15:40:19 -0400444 last_status = -ESHUTDOWN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445
David Brownella082b5c2008-04-10 14:21:06 -0700446 /* this qtd is active; skip it unless a previous qtd
447 * for its urb faulted, or its urb was canceled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 */
David Brownella082b5c2008-04-10 14:21:06 -0700449 else if (last_status == -EINPROGRESS && !urb->unlinked)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 continue;
David Brownell53bd6a62006-08-30 14:50:06 -0700451
Alan Sternfeca7742013-03-01 10:51:15 -0500452 /*
453 * If this was the active qtd when the qh was unlinked
454 * and the overlay's token is active, then the overlay
455 * hasn't been written back to the qtd yet so use its
456 * token instead of the qtd's. After the qtd is
457 * processed and removed, the overlay won't be valid
458 * any more.
459 */
460 if (state == QH_STATE_IDLE &&
461 qh->qtd_list.next == &qtd->qtd_list &&
462 (hw->hw_token & ACTIVE_BIT(ehci))) {
Alek Du3807e262009-07-14 07:23:29 +0800463 token = hc32_to_cpu(ehci, hw->hw_token);
Alan Sternfeca7742013-03-01 10:51:15 -0500464 hw->hw_token &= ~ACTIVE_BIT(ehci);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465
Alan Stern914b7012009-06-29 10:47:30 -0400466 /* An unlink may leave an incomplete
467 * async transaction in the TT buffer.
468 * We have to clear it.
469 */
470 ehci_clear_tt_buffer(ehci, qh, urb, token);
471 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 }
David Brownell53bd6a62006-08-30 14:50:06 -0700473
David Brownell4f667622008-04-12 08:32:05 -0700474 /* unless we already know the urb's status, collect qtd status
475 * and update count of bytes transferred. in common short read
476 * cases with only one data qtd (including control transfers),
477 * queue processing won't halt. but with two or more qtds (for
478 * example, with a 32 KB transfer), when the first qtd gets a
479 * short read the second must be removed by hand.
480 */
481 if (last_status == -EINPROGRESS) {
482 last_status = qtd_copy_status(ehci, urb,
483 qtd->length, token);
484 if (last_status == -EREMOTEIO
485 && (qtd->hw_alt_next
486 & EHCI_LIST_END(ehci)))
487 last_status = -EINPROGRESS;
Alan Stern914b7012009-06-29 10:47:30 -0400488
489 /* As part of low/full-speed endpoint-halt processing
490 * we must clear the TT buffer (11.17.5).
491 */
492 if (unlikely(last_status != -EINPROGRESS &&
Alan Sternc2f65952009-11-18 11:37:15 -0500493 last_status != -EREMOTEIO)) {
494 /* The TT's in some hubs malfunction when they
495 * receive this request following a STALL (they
496 * stop sending isochronous packets). Since a
497 * STALL can't leave the TT buffer in a busy
498 * state (if you believe Figures 11-48 - 11-51
499 * in the USB 2.0 spec), we won't clear the TT
500 * buffer in this case. Strictly speaking this
501 * is a violation of the spec.
502 */
503 if (last_status != -EPIPE)
504 ehci_clear_tt_buffer(ehci, qh, urb,
505 token);
506 }
Alan Sternb0d9efb2007-08-21 15:39:21 -0400507 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508
David Brownella082b5c2008-04-10 14:21:06 -0700509 /* if we're removing something not at the queue head,
510 * patch the hardware queue pointer.
511 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
513 last = list_entry (qtd->qtd_list.prev,
514 struct ehci_qtd, qtd_list);
515 last->hw_next = qtd->hw_next;
516 }
David Brownella082b5c2008-04-10 14:21:06 -0700517
518 /* remove qtd; it's recycled after possible urb completion */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 list_del (&qtd->qtd_list);
520 last = qtd;
Alan Sterna2c27062009-02-10 10:16:58 -0500521
522 /* reinit the xacterr counter for the next qtd */
Alan Sternef4638f2009-07-31 10:41:40 -0400523 qh->xacterrs = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 }
525
526 /* last urb's completion might still need calling */
527 if (likely (last != NULL)) {
Alan Stern14c04c02007-08-24 15:40:19 -0400528 ehci_urb_done(ehci, last->urb, last_status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 count++;
530 ehci_qtd_free (ehci, last);
531 }
532
Alan Stern3a444942009-08-19 12:22:06 -0400533 /* Do we need to rescan for URBs dequeued during a giveback? */
534 if (unlikely(qh->needs_rescan)) {
535 /* If the QH is already unlinked, do the rescan now. */
536 if (state == QH_STATE_IDLE)
537 goto rescan;
538
539 /* Otherwise we have to wait until the QH is fully unlinked.
540 * Our caller will start an unlink if qh->needs_rescan is
541 * set. But if an unlink has already started, nothing needs
542 * to be done.
543 */
544 if (state != QH_STATE_LINKED)
545 qh->needs_rescan = 0;
546 }
547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 /* restore original state; caller must unlink or relink */
549 qh->qh_state = state;
550
551 /* be sure the hardware's done with the qh before refreshing
552 * it after fault cleanup, or recovering from silicon wrongly
553 * overlaying the dummy qtd (which reduces DMA chatter).
554 */
Alek Du3807e262009-07-14 07:23:29 +0800555 if (stopped != 0 || hw->hw_qtd_next == EHCI_LIST_END(ehci)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 switch (state) {
557 case QH_STATE_IDLE:
558 qh_refresh(ehci, qh);
559 break;
560 case QH_STATE_LINKED:
David Brownella082b5c2008-04-10 14:21:06 -0700561 /* We won't refresh a QH that's linked (after the HC
562 * stopped the queue). That avoids a race:
563 * - HC reads first part of QH;
564 * - CPU updates that first part and the token;
565 * - HC reads rest of that QH, including token
566 * Result: HC gets an inconsistent image, and then
567 * DMAs to/from the wrong memory (corrupting it).
568 *
569 * That should be rare for interrupt transfers,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 * except maybe high bandwidth ...
571 */
Alan Sterna448c9d2009-08-19 12:22:44 -0400572
573 /* Tell the caller to start an unlink */
574 qh->needs_rescan = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 break;
576 /* otherwise, unlink already started */
577 }
578 }
579
580 return count;
581}
582
583/*-------------------------------------------------------------------------*/
584
585// high bandwidth multiplier, as encoded in highspeed endpoint descriptors
586#define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
587// ... and packet size, for any kind of endpoint descriptor
588#define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)
589
590/*
591 * reverse of qh_urb_transaction: free a list of TDs.
592 * used for cleanup after errors, before HC sees an URB's TDs.
593 */
594static void qtd_list_free (
595 struct ehci_hcd *ehci,
596 struct urb *urb,
597 struct list_head *qtd_list
598) {
599 struct list_head *entry, *temp;
600
601 list_for_each_safe (entry, temp, qtd_list) {
602 struct ehci_qtd *qtd;
603
604 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
605 list_del (&qtd->qtd_list);
606 ehci_qtd_free (ehci, qtd);
607 }
608}
609
610/*
611 * create a list of filled qtds for this URB; won't link into qh.
612 */
613static struct list_head *
614qh_urb_transaction (
615 struct ehci_hcd *ehci,
616 struct urb *urb,
617 struct list_head *head,
Al Viro55016f12005-10-21 03:21:58 -0400618 gfp_t flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619) {
620 struct ehci_qtd *qtd, *qtd_prev;
621 dma_addr_t buf;
Alan Stern40f8db82009-11-06 12:29:40 -0500622 int len, this_sg_len, maxpacket;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 int is_input;
624 u32 token;
Alan Stern40f8db82009-11-06 12:29:40 -0500625 int i;
626 struct scatterlist *sg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627
628 /*
629 * URBs map to sequences of QTDs: one logical transaction
630 */
631 qtd = ehci_qtd_alloc (ehci, flags);
632 if (unlikely (!qtd))
633 return NULL;
634 list_add_tail (&qtd->qtd_list, head);
635 qtd->urb = urb;
636
637 token = QTD_STS_ACTIVE;
638 token |= (EHCI_TUNE_CERR << 10);
639 /* for split transactions, SplitXState initialized to zero */
640
641 len = urb->transfer_buffer_length;
642 is_input = usb_pipein (urb->pipe);
643 if (usb_pipecontrol (urb->pipe)) {
644 /* SETUP pid */
Stefan Roese6dbd6822007-05-01 09:29:37 -0700645 qtd_fill(ehci, qtd, urb->setup_dma,
646 sizeof (struct usb_ctrlrequest),
647 token | (2 /* "setup" */ << 8), 8);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648
649 /* ... and always at least one more pid */
650 token ^= QTD_TOGGLE;
651 qtd_prev = qtd;
652 qtd = ehci_qtd_alloc (ehci, flags);
653 if (unlikely (!qtd))
654 goto cleanup;
655 qtd->urb = urb;
Stefan Roese6dbd6822007-05-01 09:29:37 -0700656 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 list_add_tail (&qtd->qtd_list, head);
Alan Stern69123542005-11-03 11:44:49 -0500658
659 /* for zero length DATA stages, STATUS is always IN */
660 if (len == 0)
661 token |= (1 /* "in" */ << 8);
David Brownell53bd6a62006-08-30 14:50:06 -0700662 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663
664 /*
665 * data transfer stage: buffer setup
666 */
Clemens Ladischbc677d52011-12-03 23:41:31 +0100667 i = urb->num_mapped_sgs;
Alan Stern40f8db82009-11-06 12:29:40 -0500668 if (len > 0 && i > 0) {
Matthew Wilcox910f8d02010-05-01 12:20:01 -0600669 sg = urb->sg;
Alan Stern40f8db82009-11-06 12:29:40 -0500670 buf = sg_dma_address(sg);
671
672 /* urb->transfer_buffer_length may be smaller than the
673 * size of the scatterlist (or vice versa)
674 */
675 this_sg_len = min_t(int, sg_dma_len(sg), len);
676 } else {
677 sg = NULL;
678 buf = urb->transfer_dma;
679 this_sg_len = len;
680 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681
Alan Stern69123542005-11-03 11:44:49 -0500682 if (is_input)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 token |= (1 /* "in" */ << 8);
684 /* else it's already initted to "out" pid (0 << 8) */
685
686 maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));
687
688 /*
689 * buffer gets wrapped in one or more qtds;
690 * last one may be "short" (including zero len)
691 * and may serve as a control status ack
692 */
693 for (;;) {
694 int this_qtd_len;
695
Alan Stern40f8db82009-11-06 12:29:40 -0500696 this_qtd_len = qtd_fill(ehci, qtd, buf, this_sg_len, token,
697 maxpacket);
698 this_sg_len -= this_qtd_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 len -= this_qtd_len;
700 buf += this_qtd_len;
David Brownella082b5c2008-04-10 14:21:06 -0700701
702 /*
703 * short reads advance to a "magic" dummy instead of the next
704 * qtd ... that forces the queue to stop, for manual cleanup.
705 * (this will usually be overridden later.)
706 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 if (is_input)
Alek Du3807e262009-07-14 07:23:29 +0800708 qtd->hw_alt_next = ehci->async->hw->hw_alt_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709
710 /* qh makes control packets use qtd toggle; maybe switch it */
711 if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
712 token ^= QTD_TOGGLE;
713
Alan Stern40f8db82009-11-06 12:29:40 -0500714 if (likely(this_sg_len <= 0)) {
715 if (--i <= 0 || len <= 0)
716 break;
717 sg = sg_next(sg);
718 buf = sg_dma_address(sg);
719 this_sg_len = min_t(int, sg_dma_len(sg), len);
720 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721
722 qtd_prev = qtd;
723 qtd = ehci_qtd_alloc (ehci, flags);
724 if (unlikely (!qtd))
725 goto cleanup;
726 qtd->urb = urb;
Stefan Roese6dbd6822007-05-01 09:29:37 -0700727 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 list_add_tail (&qtd->qtd_list, head);
729 }
730
David Brownella082b5c2008-04-10 14:21:06 -0700731 /*
732 * unless the caller requires manual cleanup after short reads,
733 * have the alt_next mechanism keep the queue running after the
734 * last data qtd (the only one, for control and most other cases).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 */
736 if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
737 || usb_pipecontrol (urb->pipe)))
Stefan Roese6dbd6822007-05-01 09:29:37 -0700738 qtd->hw_alt_next = EHCI_LIST_END(ehci);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739
740 /*
741 * control requests may need a terminating data "status" ack;
Ming Lei9a971dd2011-09-05 21:05:56 +0800742 * other OUT ones may need a terminating short packet
743 * (zero length).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 */
Alan Stern69123542005-11-03 11:44:49 -0500745 if (likely (urb->transfer_buffer_length != 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 int one_more = 0;
747
748 if (usb_pipecontrol (urb->pipe)) {
749 one_more = 1;
750 token ^= 0x0100; /* "in" <--> "out" */
751 token |= QTD_TOGGLE; /* force DATA1 */
Ming Lei9a971dd2011-09-05 21:05:56 +0800752 } else if (usb_pipeout(urb->pipe)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 && (urb->transfer_flags & URB_ZERO_PACKET)
754 && !(urb->transfer_buffer_length % maxpacket)) {
755 one_more = 1;
756 }
757 if (one_more) {
758 qtd_prev = qtd;
759 qtd = ehci_qtd_alloc (ehci, flags);
760 if (unlikely (!qtd))
761 goto cleanup;
762 qtd->urb = urb;
Stefan Roese6dbd6822007-05-01 09:29:37 -0700763 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 list_add_tail (&qtd->qtd_list, head);
765
766 /* never any data in such packets */
Stefan Roese6dbd6822007-05-01 09:29:37 -0700767 qtd_fill(ehci, qtd, 0, 0, token, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 }
769 }
770
771 /* by default, enable interrupt on urb completion */
772 if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
Stefan Roese6dbd6822007-05-01 09:29:37 -0700773 qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 return head;
775
776cleanup:
777 qtd_list_free (ehci, urb, head);
778 return NULL;
779}
780
781/*-------------------------------------------------------------------------*/
782
783// Would be best to create all qh's from config descriptors,
784// when each interface/altsetting is established. Unlink
785// any previous qh and cancel its urbs first; endpoints are
786// implicitly reset then (data toggle too).
787// That'd mean updating how usbcore talks to HCDs. (2.7?)
788
789
790/*
791 * Each QH holds a qtd list; a QH is used for everything except iso.
792 *
793 * For interrupt urbs, the scheduler must set the microframe scheduling
794 * mask(s) each time the QH gets scheduled. For highspeed, that's
795 * just one microframe in the s-mask. For split interrupt transactions
796 * there are additional complications: c-mask, maybe FSTNs.
797 */
798static struct ehci_qh *
799qh_make (
800 struct ehci_hcd *ehci,
801 struct urb *urb,
Al Viro55016f12005-10-21 03:21:58 -0400802 gfp_t flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803) {
804 struct ehci_qh *qh = ehci_qh_alloc (ehci, flags);
805 u32 info1 = 0, info2 = 0;
806 int is_input, type;
807 int maxp = 0;
David Brownell340ba5f2007-12-19 11:30:39 -0800808 struct usb_tt *tt = urb->dev->tt;
Alek Du3807e262009-07-14 07:23:29 +0800809 struct ehci_qh_hw *hw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810
811 if (!qh)
812 return qh;
813
814 /*
815 * init endpoint/device data for this QH
816 */
817 info1 |= usb_pipeendpoint (urb->pipe) << 8;
818 info1 |= usb_pipedevice (urb->pipe) << 0;
819
820 is_input = usb_pipein (urb->pipe);
821 type = usb_pipetype (urb->pipe);
822 maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);
823
David Brownellcaa9ef62008-02-08 15:08:44 -0800824 /* 1024 byte maxpacket is a hardware ceiling. High bandwidth
825 * acts like up to 3KB, but is built from smaller packets.
826 */
827 if (max_packet(maxp) > 1024) {
828 ehci_dbg(ehci, "bogus qh maxpacket %d\n", max_packet(maxp));
829 goto done;
830 }
831
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 /* Compute interrupt scheduling parameters just once, and save.
833 * - allowing for high bandwidth, how many nsec/uframe are used?
834 * - split transactions need a second CSPLIT uframe; same question
835 * - splits also need a schedule gap (for full/low speed I/O)
836 * - qh has a polling interval
837 *
838 * For control/bulk requests, the HC or TT handles these.
839 */
840 if (type == PIPE_INTERRUPT) {
David Brownell340ba5f2007-12-19 11:30:39 -0800841 qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
842 is_input, 0,
843 hb_mult(maxp) * max_packet(maxp)));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 qh->start = NO_FRAME;
845
846 if (urb->dev->speed == USB_SPEED_HIGH) {
847 qh->c_usecs = 0;
848 qh->gap_uf = 0;
849
850 qh->period = urb->interval >> 3;
851 if (qh->period == 0 && urb->interval != 1) {
852 /* NOTE interval 2 or 4 uframes could work.
853 * But interval 1 scheduling is simpler, and
854 * includes high bandwidth.
855 */
Alan Stern1b9a38b2010-01-08 11:17:55 -0500856 urb->interval = 1;
857 } else if (qh->period > ehci->periodic_size) {
858 qh->period = ehci->periodic_size;
859 urb->interval = qh->period << 3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 }
861 } else {
david-b@pacbell.netd0384202005-08-13 18:44:58 -0700862 int think_time;
863
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 /* gap is f(FS/LS transfer times) */
865 qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
866 is_input, 0, maxp) / (125 * 1000);
867
868 /* FIXME this just approximates SPLIT/CSPLIT times */
869 if (is_input) { // SPLIT, gap, CSPLIT+DATA
870 qh->c_usecs = qh->usecs + HS_USECS (0);
871 qh->usecs = HS_USECS (1);
872 } else { // SPLIT+DATA, gap, CSPLIT
873 qh->usecs += HS_USECS (1);
874 qh->c_usecs = HS_USECS (0);
875 }
876
david-b@pacbell.netd0384202005-08-13 18:44:58 -0700877 think_time = tt ? tt->think_time : 0;
878 qh->tt_usecs = NS_TO_US (think_time +
879 usb_calc_bus_time (urb->dev->speed,
880 is_input, 0, max_packet (maxp)));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 qh->period = urb->interval;
Alan Stern1b9a38b2010-01-08 11:17:55 -0500882 if (qh->period > ehci->periodic_size) {
883 qh->period = ehci->periodic_size;
884 urb->interval = qh->period;
885 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 }
887 }
888
889 /* support for tt scheduling, and access to toggles */
Alan Stern6a8e87b2006-01-19 10:46:27 -0500890 qh->dev = urb->dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891
892 /* using TT? */
893 switch (urb->dev->speed) {
894 case USB_SPEED_LOW:
Alan Stern4c53de72012-07-11 11:21:32 -0400895 info1 |= QH_LOW_SPEED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 /* FALL THROUGH */
897
898 case USB_SPEED_FULL:
899 /* EPS 0 means "full" */
900 if (type != PIPE_INTERRUPT)
901 info1 |= (EHCI_TUNE_RL_TT << 28);
902 if (type == PIPE_CONTROL) {
Alan Stern4c53de72012-07-11 11:21:32 -0400903 info1 |= QH_CONTROL_EP; /* for TT */
904 info1 |= QH_TOGGLE_CTL; /* toggle from qtd */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 }
906 info1 |= maxp << 16;
907
908 info2 |= (EHCI_TUNE_MULT_TT << 30);
Kumar Gala8cd42e92006-01-20 13:57:52 -0800909
910 /* Some Freescale processors have an erratum in which the
911 * port number in the queue head was 0..N-1 instead of 1..N.
912 */
913 if (ehci_has_fsl_portno_bug(ehci))
914 info2 |= (urb->dev->ttport-1) << 23;
915 else
916 info2 |= urb->dev->ttport << 23;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917
918 /* set the address of the TT; for TDI's integrated
919 * root hub tt, leave it zeroed.
920 */
David Brownell340ba5f2007-12-19 11:30:39 -0800921 if (tt && tt->hub != ehci_to_hcd(ehci)->self.root_hub)
922 info2 |= tt->hub->devnum << 16;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923
924 /* NOTE: if (PIPE_INTERRUPT) { scheduler sets c-mask } */
925
926 break;
927
928 case USB_SPEED_HIGH: /* no TT involved */
Alan Stern4c53de72012-07-11 11:21:32 -0400929 info1 |= QH_HIGH_SPEED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 if (type == PIPE_CONTROL) {
931 info1 |= (EHCI_TUNE_RL_HS << 28);
932 info1 |= 64 << 16; /* usb2 fixed maxpacket */
Alan Stern4c53de72012-07-11 11:21:32 -0400933 info1 |= QH_TOGGLE_CTL; /* toggle from qtd */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 info2 |= (EHCI_TUNE_MULT_HS << 30);
935 } else if (type == PIPE_BULK) {
936 info1 |= (EHCI_TUNE_RL_HS << 28);
David Brownellcaa9ef62008-02-08 15:08:44 -0800937 /* The USB spec says that high speed bulk endpoints
938 * always use 512 byte maxpacket. But some device
939 * vendors decided to ignore that, and MSFT is happy
940 * to help them do so. So now people expect to use
941 * such nonconformant devices with Linux too; sigh.
942 */
943 info1 |= max_packet(maxp) << 16;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944 info2 |= (EHCI_TUNE_MULT_HS << 30);
945 } else { /* PIPE_INTERRUPT */
946 info1 |= max_packet (maxp) << 16;
947 info2 |= hb_mult (maxp) << 30;
948 }
949 break;
950 default:
Greg Kroah-Hartman82491c22012-05-01 21:33:35 -0700951 ehci_dbg(ehci, "bogus dev %p speed %d\n", urb->dev,
952 urb->dev->speed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953done:
Alan Sternc83e1a92012-07-11 11:21:25 -0400954 qh_destroy(ehci, qh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 return NULL;
956 }
957
958 /* NOTE: if (PIPE_INTERRUPT) { scheduler sets s-mask } */
959
960 /* init as live, toggle clear, advance to dummy */
961 qh->qh_state = QH_STATE_IDLE;
Alek Du3807e262009-07-14 07:23:29 +0800962 hw = qh->hw;
963 hw->hw_info1 = cpu_to_hc32(ehci, info1);
964 hw->hw_info2 = cpu_to_hc32(ehci, info2);
Alan Sterne04f5f72011-07-19 14:01:23 -0400965 qh->is_out = !is_input;
Alan Sterna455212d2009-06-11 14:56:22 -0400966 usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 qh_refresh (ehci, qh);
968 return qh;
969}
970
971/*-------------------------------------------------------------------------*/
972
Alan Stern31446612012-07-11 11:22:21 -0400973static void enable_async(struct ehci_hcd *ehci)
974{
975 if (ehci->async_count++)
976 return;
977
978 /* Stop waiting to turn off the async schedule */
979 ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_ASYNC);
980
981 /* Don't start the schedule until ASS is 0 */
982 ehci_poll_ASS(ehci);
Alan Stern18aafe62012-07-11 11:23:04 -0400983 turn_on_io_watchdog(ehci);
Alan Stern31446612012-07-11 11:22:21 -0400984}
985
986static void disable_async(struct ehci_hcd *ehci)
987{
988 if (--ehci->async_count)
989 return;
990
991 /* The async schedule and async_unlink list are supposed to be empty */
992 WARN_ON(ehci->async->qh_next.qh || ehci->async_unlink);
993
994 /* Don't turn off the schedule until ASS is 1 */
995 ehci_poll_ASS(ehci);
996}
997
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998/* move qh (and its qtds) onto async queue; maybe enable queue. */
999
1000static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
1001{
Stefan Roese6dbd6822007-05-01 09:29:37 -07001002 __hc32 dma = QH_NEXT(ehci, qh->qh_dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 struct ehci_qh *head;
1004
Alan Stern914b7012009-06-29 10:47:30 -04001005 /* Don't link a QH if there's a Clear-TT-Buffer pending */
1006 if (unlikely(qh->clearing_tt))
1007 return;
1008
Alan Stern3a444942009-08-19 12:22:06 -04001009 WARN_ON(qh->qh_state != QH_STATE_IDLE);
1010
Alan Sterna455212d2009-06-11 14:56:22 -04001011 /* clear halt and/or toggle; and maybe recover from silicon quirk */
Alan Stern3a444942009-08-19 12:22:06 -04001012 qh_refresh(ehci, qh);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013
1014 /* splice right after start */
Alan Stern31446612012-07-11 11:22:21 -04001015 head = ehci->async;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 qh->qh_next = head->qh_next;
Alek Du3807e262009-07-14 07:23:29 +08001017 qh->hw->hw_next = head->hw->hw_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 wmb ();
1019
1020 head->qh_next.qh = qh;
Alek Du3807e262009-07-14 07:23:29 +08001021 head->hw->hw_next = dma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022
Alan Sternef4638f2009-07-31 10:41:40 -04001023 qh->xacterrs = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 qh->qh_state = QH_STATE_LINKED;
1025 /* qtd completions reported later by interrupt */
Alan Stern31446612012-07-11 11:22:21 -04001026
1027 enable_async(ehci);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028}
1029
1030/*-------------------------------------------------------------------------*/
1031
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032/*
1033 * For control/bulk/interrupt, return QH with these TDs appended.
1034 * Allocates and initializes the QH if necessary.
1035 * Returns null if it can't allocate a QH it needs to.
1036 * If the QH has TDs (urbs) already, that's great.
1037 */
1038static struct ehci_qh *qh_append_tds (
1039 struct ehci_hcd *ehci,
1040 struct urb *urb,
1041 struct list_head *qtd_list,
1042 int epnum,
1043 void **ptr
1044)
1045{
1046 struct ehci_qh *qh = NULL;
Al Virofd05e722008-04-28 07:00:16 +01001047 __hc32 qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048
1049 qh = (struct ehci_qh *) *ptr;
1050 if (unlikely (qh == NULL)) {
1051 /* can't sleep here, we have ehci->lock... */
1052 qh = qh_make (ehci, urb, GFP_ATOMIC);
1053 *ptr = qh;
1054 }
1055 if (likely (qh != NULL)) {
1056 struct ehci_qtd *qtd;
1057
1058 if (unlikely (list_empty (qtd_list)))
1059 qtd = NULL;
1060 else
1061 qtd = list_entry (qtd_list->next, struct ehci_qtd,
1062 qtd_list);
1063
1064 /* control qh may need patching ... */
1065 if (unlikely (epnum == 0)) {
1066
1067 /* usb_reset_device() briefly reverts to address 0 */
1068 if (usb_pipedevice (urb->pipe) == 0)
Alek Du3807e262009-07-14 07:23:29 +08001069 qh->hw->hw_info1 &= ~qh_addr_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 }
1071
1072 /* just one way to queue requests: swap with the dummy qtd.
1073 * only hc or qh_refresh() ever modify the overlay.
1074 */
1075 if (likely (qtd != NULL)) {
1076 struct ehci_qtd *dummy;
1077 dma_addr_t dma;
Stefan Roese6dbd6822007-05-01 09:29:37 -07001078 __hc32 token;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079
1080 /* to avoid racing the HC, use the dummy td instead of
1081 * the first td of our list (becomes new dummy). both
1082 * tds stay deactivated until we're done, when the
1083 * HC is allowed to fetch the old dummy (4.10.2).
1084 */
1085 token = qtd->hw_token;
Stefan Roese6dbd6822007-05-01 09:29:37 -07001086 qtd->hw_token = HALT_BIT(ehci);
Ming Lei41f05de2011-09-05 21:05:58 +08001087
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 dummy = qh->dummy;
1089
1090 dma = dummy->qtd_dma;
1091 *dummy = *qtd;
1092 dummy->qtd_dma = dma;
1093
1094 list_del (&qtd->qtd_list);
1095 list_add (&dummy->qtd_list, qtd_list);
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -07001096 list_splice_tail(qtd_list, &qh->qtd_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097
Stefan Roese6dbd6822007-05-01 09:29:37 -07001098 ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 qh->dummy = qtd;
1100
1101 /* hc must see the new dummy at list end */
1102 dma = qtd->qtd_dma;
1103 qtd = list_entry (qh->qtd_list.prev,
1104 struct ehci_qtd, qtd_list);
Stefan Roese6dbd6822007-05-01 09:29:37 -07001105 qtd->hw_next = QTD_NEXT(ehci, dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106
1107 /* let the hc process these next qtds */
1108 wmb ();
1109 dummy->hw_token = token;
1110
Alan Sternc83e1a92012-07-11 11:21:25 -04001111 urb->hcpriv = qh;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 }
1113 }
1114 return qh;
1115}
1116
1117/*-------------------------------------------------------------------------*/
1118
1119static int
1120submit_async (
1121 struct ehci_hcd *ehci,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 struct urb *urb,
1123 struct list_head *qtd_list,
Al Viro55016f12005-10-21 03:21:58 -04001124 gfp_t mem_flags
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126 int epnum;
1127 unsigned long flags;
1128 struct ehci_qh *qh = NULL;
Alan Sterne9df41c2007-08-08 11:48:02 -04001129 int rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130
Alan Sterne9df41c2007-08-08 11:48:02 -04001131 epnum = urb->ep->desc.bEndpointAddress;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132
1133#ifdef EHCI_URB_TRACE
David Daneyeb34a902011-01-25 09:59:36 -08001134 {
1135 struct ehci_qtd *qtd;
1136 qtd = list_entry(qtd_list->next, struct ehci_qtd, qtd_list);
1137 ehci_dbg(ehci,
1138 "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
1139 __func__, urb->dev->devpath, urb,
1140 epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
1141 urb->transfer_buffer_length,
1142 qtd, urb->ep->hcpriv);
1143 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144#endif
1145
1146 spin_lock_irqsave (&ehci->lock, flags);
Alan Stern541c7d42010-06-22 16:39:10 -04001147 if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001148 rc = -ESHUTDOWN;
1149 goto done;
1150 }
Alan Sterne9df41c2007-08-08 11:48:02 -04001151 rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
1152 if (unlikely(rc))
1153 goto done;
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001154
Alan Sterne9df41c2007-08-08 11:48:02 -04001155 qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001156 if (unlikely(qh == NULL)) {
Alan Sterne9df41c2007-08-08 11:48:02 -04001157 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001158 rc = -ENOMEM;
1159 goto done;
1160 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161
1162 /* Control/bulk operations through TTs don't need scheduling,
1163 * the HC and TT handle it when the TT has a buffer ready.
1164 */
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001165 if (likely (qh->qh_state == QH_STATE_IDLE))
Alan Stern7a0f0d92009-07-31 10:40:22 -04001166 qh_link_async(ehci, qh);
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001167 done:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168 spin_unlock_irqrestore (&ehci->lock, flags);
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001169 if (unlikely (qh == NULL))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 qtd_list_free (ehci, urb, qtd_list);
Benjamin Herrenschmidt8de98402005-11-25 09:59:46 +11001171 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172}
1173
1174/*-------------------------------------------------------------------------*/
1175
Alan Stern3c273a02012-07-11 11:22:49 -04001176static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177{
Alan Stern3c273a02012-07-11 11:22:49 -04001178 struct ehci_qh *prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179
Alan Stern3c273a02012-07-11 11:22:49 -04001180 /* Add to the end of the list of QHs waiting for the next IAAD */
Alan Stern6402c792013-03-01 10:50:08 -05001181 qh->qh_state = QH_STATE_UNLINK_WAIT;
Alan Stern3c273a02012-07-11 11:22:49 -04001182 if (ehci->async_unlink)
1183 ehci->async_unlink_last->unlink_next = qh;
1184 else
1185 ehci->async_unlink = qh;
1186 ehci->async_unlink_last = qh;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187
Alan Stern3c273a02012-07-11 11:22:49 -04001188 /* Unlink it from the schedule */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 prev = ehci->async;
1190 while (prev->qh_next.qh != qh)
1191 prev = prev->qh_next.qh;
1192
Alek Du3807e262009-07-14 07:23:29 +08001193 prev->hw->hw_next = qh->hw->hw_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 prev->qh_next = qh->qh_next;
Alan Stern004c1962011-07-05 12:34:05 -04001195 if (ehci->qh_scan_next == qh)
1196 ehci->qh_scan_next = qh->qh_next.qh;
Alan Stern3c273a02012-07-11 11:22:49 -04001197}
1198
1199static void start_iaa_cycle(struct ehci_hcd *ehci, bool nested)
1200{
1201 /*
1202 * Do nothing if an IAA cycle is already running or
1203 * if one will be started shortly.
1204 */
1205 if (ehci->async_iaa || ehci->async_unlinking)
1206 return;
1207
Alan Stern391016f2009-03-16 14:21:56 -04001208 /* If the controller isn't running, we don't have to wait for it */
Alan Sternc0c53db2012-07-11 11:21:48 -04001209 if (unlikely(ehci->rh_state < EHCI_RH_RUNNING)) {
Alan Stern6e0c3332013-01-25 16:54:22 -05001210
1211 /* Do all the waiting QHs */
1212 ehci->async_iaa = ehci->async_unlink;
1213 ehci->async_unlink = NULL;
1214
Alan Stern3c273a02012-07-11 11:22:49 -04001215 if (!nested) /* Avoid recursion */
1216 end_unlink_async(ehci);
1217
1218 /* Otherwise start a new IAA cycle */
Alan Stern32830f22012-07-11 11:22:53 -04001219 } else if (likely(ehci->rh_state == EHCI_RH_RUNNING)) {
Alan Stern6e0c3332013-01-25 16:54:22 -05001220 struct ehci_qh *qh;
1221
1222 /* Do only the first waiting QH (nVidia bug?) */
1223 qh = ehci->async_unlink;
Alan Stern6402c792013-03-01 10:50:08 -05001224
1225 /*
1226 * Intel (?) bug: The HC can write back the overlay region
1227 * even after the IAA interrupt occurs. In self-defense,
1228 * always go through two IAA cycles for each QH.
1229 */
1230 if (qh->qh_state == QH_STATE_UNLINK_WAIT) {
1231 qh->qh_state = QH_STATE_UNLINK;
1232 } else {
1233 ehci->async_iaa = qh;
1234 ehci->async_unlink = qh->unlink_next;
1235 qh->unlink_next = NULL;
1236 }
Alan Stern6e0c3332013-01-25 16:54:22 -05001237
Alan Stern3c273a02012-07-11 11:22:49 -04001238 /* Make sure the unlinks are all visible to the hardware */
1239 wmb();
1240
1241 ehci_writel(ehci, ehci->command | CMD_IAAD,
1242 &ehci->regs->command);
1243 ehci_readl(ehci, &ehci->regs->command);
1244 ehci_enable_event(ehci, EHCI_HRTIMER_IAA_WATCHDOG, true);
1245 }
1246}
1247
1248/* the async qh for the qtds being unlinked are now gone from the HC */
1249
1250static void end_unlink_async(struct ehci_hcd *ehci)
1251{
1252 struct ehci_qh *qh;
1253
1254 if (ehci->has_synopsys_hc_bug)
1255 ehci_writel(ehci, (u32) ehci->async->qh_dma,
1256 &ehci->regs->async_next);
1257
1258 /* Process the idle QHs */
1259 restart:
1260 ehci->async_unlinking = true;
1261 while (ehci->async_iaa) {
1262 qh = ehci->async_iaa;
1263 ehci->async_iaa = qh->unlink_next;
1264 qh->unlink_next = NULL;
1265
1266 qh->qh_state = QH_STATE_IDLE;
1267 qh->qh_next.qh = NULL;
1268
1269 qh_completions(ehci, qh);
1270 if (!list_empty(&qh->qtd_list) &&
1271 ehci->rh_state == EHCI_RH_RUNNING)
1272 qh_link_async(ehci, qh);
1273 disable_async(ehci);
1274 }
1275 ehci->async_unlinking = false;
1276
1277 /* Start a new IAA cycle if any QHs are waiting for it */
1278 if (ehci->async_unlink) {
1279 start_iaa_cycle(ehci, true);
1280 if (unlikely(ehci->rh_state < EHCI_RH_RUNNING))
1281 goto restart;
1282 }
1283}
1284
Alan Stern6e0c3332013-01-25 16:54:22 -05001285static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh);
1286
Alan Stern32830f22012-07-11 11:22:53 -04001287static void unlink_empty_async(struct ehci_hcd *ehci)
1288{
Alan Stern6e0c3332013-01-25 16:54:22 -05001289 struct ehci_qh *qh;
1290 struct ehci_qh *qh_to_unlink = NULL;
Alan Stern32830f22012-07-11 11:22:53 -04001291 bool check_unlinks_later = false;
Alan Stern6e0c3332013-01-25 16:54:22 -05001292 int count = 0;
Alan Stern32830f22012-07-11 11:22:53 -04001293
Alan Stern6e0c3332013-01-25 16:54:22 -05001294 /* Find the last async QH which has been empty for a timer cycle */
1295 for (qh = ehci->async->qh_next.qh; qh; qh = qh->qh_next.qh) {
Alan Stern32830f22012-07-11 11:22:53 -04001296 if (list_empty(&qh->qtd_list) &&
1297 qh->qh_state == QH_STATE_LINKED) {
Alan Stern6e0c3332013-01-25 16:54:22 -05001298 ++count;
1299 if (qh->unlink_cycle == ehci->async_unlink_cycle)
Alan Stern32830f22012-07-11 11:22:53 -04001300 check_unlinks_later = true;
1301 else
Alan Stern6e0c3332013-01-25 16:54:22 -05001302 qh_to_unlink = qh;
Alan Stern32830f22012-07-11 11:22:53 -04001303 }
1304 }
1305
Alan Stern6e0c3332013-01-25 16:54:22 -05001306 /* If nothing else is being unlinked, unlink the last empty QH */
1307 if (!ehci->async_iaa && !ehci->async_unlink && qh_to_unlink) {
1308 start_unlink_async(ehci, qh_to_unlink);
1309 --count;
1310 }
Alan Stern32830f22012-07-11 11:22:53 -04001311
Alan Stern6e0c3332013-01-25 16:54:22 -05001312 /* Other QHs will be handled later */
1313 if (count > 0) {
Alan Stern32830f22012-07-11 11:22:53 -04001314 ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
1315 ++ehci->async_unlink_cycle;
1316 }
1317}
1318
Alan Stern3c273a02012-07-11 11:22:49 -04001319/* makes sure the async qh will become idle */
1320/* caller must own ehci->lock */
1321
1322static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
1323{
1324 /*
1325 * If the QH isn't linked then there's nothing we can do
1326 * unless we were called during a giveback, in which case
1327 * qh_completions() has to deal with it.
1328 */
1329 if (qh->qh_state != QH_STATE_LINKED) {
1330 if (qh->qh_state == QH_STATE_COMPLETING)
1331 qh->needs_rescan = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 return;
1333 }
1334
Alan Stern3c273a02012-07-11 11:22:49 -04001335 single_unlink_async(ehci, qh);
1336 start_iaa_cycle(ehci, false);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337}
1338
1339/*-------------------------------------------------------------------------*/
1340
David Howells7d12e782006-10-05 14:55:46 +01001341static void scan_async (struct ehci_hcd *ehci)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342{
1343 struct ehci_qh *qh;
Alan Stern32830f22012-07-11 11:22:53 -04001344 bool check_unlinks_later = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
Alan Stern004c1962011-07-05 12:34:05 -04001346 ehci->qh_scan_next = ehci->async->qh_next.qh;
1347 while (ehci->qh_scan_next) {
1348 qh = ehci->qh_scan_next;
1349 ehci->qh_scan_next = qh->qh_next.qh;
1350 rescan:
1351 /* clean any finished work for this qh */
1352 if (!list_empty(&qh->qtd_list)) {
1353 int temp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354
Alan Stern004c1962011-07-05 12:34:05 -04001355 /*
1356 * Unlinks could happen here; completion reporting
1357 * drops the lock. That's why ehci->qh_scan_next
1358 * always holds the next qh to scan; if the next qh
1359 * gets unlinked then ehci->qh_scan_next is adjusted
Alan Stern3c273a02012-07-11 11:22:49 -04001360 * in single_unlink_async().
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 */
Alan Stern004c1962011-07-05 12:34:05 -04001362 temp = qh_completions(ehci, qh);
Alan Stern32830f22012-07-11 11:22:53 -04001363 if (qh->needs_rescan) {
Alan Stern3c273a02012-07-11 11:22:49 -04001364 start_unlink_async(ehci, qh);
Alan Stern32830f22012-07-11 11:22:53 -04001365 } else if (list_empty(&qh->qtd_list)
1366 && qh->qh_state == QH_STATE_LINKED) {
1367 qh->unlink_cycle = ehci->async_unlink_cycle;
1368 check_unlinks_later = true;
1369 } else if (temp != 0)
Alan Stern004c1962011-07-05 12:34:05 -04001370 goto rescan;
1371 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 }
Alan Stern32830f22012-07-11 11:22:53 -04001373
1374 /*
1375 * Unlink empty entries, reducing DMA usage as well
1376 * as HCD schedule-scanning costs. Delay for any qh
1377 * we just scanned, there's a not-unusual case that it
1378 * doesn't stay idle for long.
1379 */
1380 if (check_unlinks_later && ehci->rh_state == EHCI_RH_RUNNING &&
1381 !(ehci->enabled_hrtimer_events &
1382 BIT(EHCI_HRTIMER_ASYNC_UNLINKS))) {
1383 ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
1384 ++ehci->async_unlink_cycle;
1385 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386}